Update 'README.md'

README.md

@@ -23,4 +23,4 @@
 
 [Demo with synthetic data](https://gin.g-node.org/56Fe/Analysis-of-Current-Source-Density/src/master/demo.m)
 
-![Demo with synthetic data](https://gin.g-node.org/56Fe/Analysis-of-Current-Source-Density/src/master/PLOT_iCSD.png)
+![Demo with synthetic data](https://gin.g-node.org/56Fe/Analysis-of-Current-Source-Density/raw/master/PLOT_iCSD.png)